The Earth geometry tool allows you to create dynamic diagrams that demonstrate the geometry of travel paths.
Video - Earth Geometry
The tool can draw both great circle paths as well as paths restricted to lines of latitude and longitude as show above. It also comes with a database of over 13000 cities that allow you to quickly build questions.
To use the tool, sweep out a rectangle and a globe will appear. Right click on the globe to create a path.
1. You have five different rendering styles for your globe.
2. To create a path, enter starting and finishing locations. You can enter just a latitude and longitude or you can give a place a name. The following inputs are all valid.
Perth (-32,116)
14N125W
London 42N,-120
Note, as demonstrated by the last entry, that what you type does not need to be true!
Pushing the Search buttons allow you to access the database of locations.
a) Start typing anything which appears in the location's name or country.
b) The tool will show you locations which fit your entered name. Typing part of a country name will allow you to find just locations in that county.
c) You can also enter latitudes and longitudes to search for. This allows you to search for locations on the same lines of latitude or longitude.
Once you have found a location, push OK and you will be returned to the main path screen with (by default) rounded versions of the latitude and longitude. You can modify these as required. Note that the tool calculates the length of your selected path based on the entered earth radius.
3. Once you have created your path, you can modify the display using the various tools on this screen. The transparency slider allows you to turn a path on the surface into a diagram that shows the underlying geometry. You also have the option to auto-rotate the globe which can be useful for demonstration purposes.